DC Lines LMS Searchlight Signals

There is another shot on this page:
www.roscalen.com/signals/London/CWJ.htm

The main searchlight aspect at the top only uses a single filament lamp and therefore the filament burning out would leave a blank signal. The circuitry was arranged that when the signal displays a red aspect (also the yellow aspect between 1933 and 1936) that the red marker light also would show in the upper of the two lower aspects. Therefore if the searchlight was blank then a red aspect would show for red (or yellow as shown above) positions of the searchlight mechanisms. The lowest aspect was the best feature of this system and comprised of a reduced size yellow aspect as a call-on facility. A train arriving at a red signal (automatic or semi automatic working in auto) would occupy the berth track circuit. After an 80 second timer had operated, the red marker light would go out and the call-on light up. This facility worked at all times irrespective of whether the signal had failed or not and allowed for some very interesting combinations of trains nose to tail, it could be said to be true passenger permissive. There were other signals where the yellow call-on was not provided and an example is seen at Watford High St where owing to the steep gradient to Watford Jcn it was advisable not to follow as it was possible to come to a stand over the catch points. At Croxley Green Jcn the only searchlights provided only had the red marker lights as no auto working was possible and the signals reading on and off the deport were mechanical.

Excellent Paul - I was going to give the link to Clive DW Feather[...]'s stuff, and the article (if you want it) is in LMS Journal No 27. It is a good read in its own right.

Does this help?:



from the 1981 Bakerloo Section 11 Appendix Supplement.

EDIT: AFAIAA Croxley Green Junction stayed semaphore until remodelling: but I'm willing to be corrected on that. ie. The New lines signalling didn't go out that far until the simplification with the GPL 'S1' and the addition of WJ 128 - which I suspect came along with the opening of Watfrod PSB and the ingenious ARS circuitry.

No, unfortunately, but if you hang on a tick; I've got something up my sleeve! Wait and see......

Howzat?

Trailing traps IIRC to stop something breaking away and surprising the station staff.